The tail of a crashed AirAsia jet has been found on the sea bed about 30 km (20 miles) from the plane’s last known location, Indonesia’s search and rescue agency said on Wednesday.

The tail of a crashed AirAsia jet has been found on the sea bed about 30 km (20 miles) from the plane's last known location, Indonesia's search and rescue agency said on Wednesday, a breakthrough that investigators hope will lead to the crucial black box recorders.

Flight QZ8501 vanished from radar screens over the northern Java Sea on Dec. 28, less than half-way into a two-hour flight from Indonesia's second-biggest city of Surabaya to Singapore. There were no survivors among the 162 people on board.

"We've found the tail that has been our main target," Fransiskus Bambang Soelistyo, head of the search and rescue agency, told a news conference in Jakarta.

The tail was identified by divers after it was spotted by an underwater machine using a sonar scan, Soelistyo said. He displayed underwater photographs showing partial lettering on the sunken object compared with a picture of an intact Airbus A320-200 in AirAsia livery.

"I can confirm that what we found was the tail part from the pictures," he said, adding that the team "now is still desperately trying to locate the black box".

Forty bodies and debris from the plane have been plucked from the surface of the waters off Borneo, but strong winds and high waves have been hampering divers' efforts to reach larger pieces of suspected wreckage detected by sonar on the sea floor.

Locating the tail has been a priority because the cockpit voice and flight data recorders that can provide vital clues on why the plane crashed are located in the rear section of the Airbus.